<!DOCTYPE html>
<html lang="en">
<head>
    <meta charset="UTF-8">
    <meta http-equiv="X-UA-Compatible" content="IE=edge">
    <meta name="viewport" content="width=device-width, initial-scale=1.0">
    <title>Document</title>
</head>
<script src="./js/vue.js"></script>
<body>
    <div class="box">
        <h1>{{msg}}</h1>
    </div>
    <script>
        // Object.freeze()  可以阻断数据的变化,阻止它的响应式变化
        const obj = {
                msg:'乐乐！！'
            };
            // 
        Object.freeze(obj);    
        const vm = new Vue({
            el:'.box',
            data:obj
        })
    </script>
</body>
</html>